The polymeric structure of lignocellulosic cell walls consists primarily of cellulose, hemicellulose, and lignin. Each of these components possesses hydroxyl functional groups which moderate the interaction of water with the lignocellulosic material. For example, lignocellulosic materials such as wood may swell under moist conditions, in large part due to hydrogen bonding between water and the hydroxyl groups on the cell wall components. Many chemical-based wood treatment methods rely on covalently modifying the hydroxyl groups of cell walls, to improve a variety of wood properties such as hardness, dimensional stability, resistance to UV light, and resistance to decay. For example, in acetylation, hydroxyl groups are reacted with acetic anhydride to incorporate acetyl groups on to the cell walls of the wood. Both through reduction of free hydroxyl functionality and through incorporation of less polar groups, the acetylated wood exhibits a marked decrease in its ability to absorb water. Incorporation of large acetyl groups also serves to bulk the cell walls of the material, further blocking water absorption pathways. As a result, in comparison to untreated wood, acetylated wood demonstrates much better ability to resist attack by wood-decaying organisms such as brown, white, and soft rot fungi.
Despite the aforementioned advantages of acetylation as a wood preservation technique, the method suffers from drawbacks. In particular, acetylation requires the use of a difficult-to-handle chemical reagent (acetic anhydride) which produces a stench byproduct (acetic acid) that must either be recycled or disposed. Furthermore, since acetylation processes are typically tailored to chemically modify most or all of the hydroxyl functionality of wood, large volumes of acetic anhydride are necessary.